Analysis of herpes simplex virus DNA synthesized in vitro in nuclei isolated from infected BSC-1 cells

Herpes simplex virus (HSV) DNA molecules synthesized in isolated nuclei in vitro were analyzed by centrifugation in sucrose gradients and by chromatography on benzoylated naphthoylated DEAE (BND)-cellulose columns. Some of the in vitro synthesized viral DNA molecules were found to have a high molecular weight when cosedimented with a HSV-DNA marker. Over 60% of the in vitro labeled DNA molecules were eluted from the BND-cellulose columns by 1.0 M NaCl containing 2% caffeine, indicating the presence of single-stranded sequences in the DNA molecules, a property of replicating DNA molecules. It is concluded that under in vitro conditions, the elongation of nascent viral DNA molecules takes place.